1. Technical Field
This invention relates to animal stanchions, and more particularly to automatic locking cattle stanchions having opened, closed and downed animal positions.
2. Background
Safety stanchions to hold, and selectively release cows during feeding, milking, veterinary care, pregnancy testing and even calving, are very commonly used throughout the United States. They are found in feed lots, ranching operations, dairies and virtually any other activity where cattle and dairy cows are tended to. They have some common characteristics, in that they are usually fabricated in long strings of individual stanchions connected between top and bottom rails and set in concrete which are used to separate the animals from the feed bunker.
In the typical prior art cattle stanchion being manufactured today, the head opening for the animal is typically defined between a stationary, vertically-oriented stanchion, and a pivotal release stanchion, which when tilted in one direction enlarges the upper part of the opening so that the animal can put its head through. As the animal lowers its head to reach the feed, the pivotal release stanchion pivots to a more vertical position, where it automatically latches in place to define the closed position. In the closed position the animal cannot withdraw its head from the stanchion and is effectively held in place. If the animal becomes distressed and falls down, or is knocked down by an adjacent animal, the stanchion can be individually released to a downed cow position by releasing the latch on the release stanchion and allowing it to pivot in the opposite direction to enlarge the opening in the lower portion of the head opening so that the downed animal can remove its head.
These long strings of cattle stanchions serve many useful functions which include, but are not limited to, permitting each animal equal access to the feed bunker for equal portion sizing, for holding the animals close together where they are most comfortable since they are instinctually herd animals, and to immobilize the animal for veterinary care, such as dehorning, vaccinating, pregnancy testing and a host of other types of uses.
Control of the latch mechanism for the release stanchion in the prior art has traditionally been accomplished by means of a control rod, which is mounted atop the top rail. In the prior art the control rod contains one of two cooperating parts of a latch mechanism for the release stanchion, with the other cooperating part of the latch mechanism attached to the top of the pivotal release stanchion. The typical prior art safety stanchion assembly contains a control rod which provides for the following lock and release functions: a locked open position where the release stanchion automatically falls to the open position where the upper portion of the opening is enlarged to enable an animal to insert its head and then lower its head, swinging the release stanchion out of the way as it reaches for feed; an open to automatic closed position where when the animal lowers its head the release stanchion locks in place in the closed position to automatically lock the animal in the stanchion; a manually operable downed cow position wherein the rancher or dairyman can release an individual animal that has fallen down by manually pivoting the release stanchion to the downed cow position; and a locked closed position to lock all of the stanchions in a closed position to either keep the animals from inserting their heads through the stanchions, or to keep all of the animals contained within the stanchions.
Considerable effort has been expended in the prior art to build safe to operate and effective latching mechanisms. The reason for this is the safety issue, since large animals can exert considerable and sudden forces to the pivotal release stanchions, especially when startled or distressed.
The problem in the prior art comes not from the effectiveness of the prior art latching mechanisms, although some latching mechanisms work much better than others, but rather from the fundamental design which requires one cooperating part of the latch mechanism is attached to the pivotal release stanchion, and the other is attached to the control rod which is mounted above the top rail. Since they must be stoutly built to restrain the animals, strings of cattle stanchions are fabricated of metal, usually steel and metal, including steel, expands and contracts with changes in temperature. Since these continuous strings of cattle stanchions can literally include hundreds of stanchions, all in one continuous row, the amount of expansion and contraction can be considerable.
In the prior art, the fixed vertical stanchions are usually anchored in concrete and firmly attached to the upper and lower rails. In a like manner, the pivotal release stanchion is also attached to a pivot support bar of some sort, which itself is attached to the upper and lower rails, thereby locking this portion of the assembly firmly together. At the same time, the control arm, which may be fabricated of a different metal alloy, is usually mounted to be both rotatable and slideable. It is normally of a different dimension than the top rail. Thus, even though it is mounted above the top rail, it is free to expand and contract differently than the rigid support structure to which it is mounted.
In the prior art, if you have a string of stanchions of any significant number, it is quite common that all of the couplers on the slideable and rotatable control arm will align with the matching latch couplers on the pivotal release stanchions in the morning when the entire assembly is cold, and in the warm summer afternoon, have enough expansion of the control arm, such that the control arm coupler mechanisms will line up with the pivotal release stanchion couplers at one end of the string, but not at the other.
As a result, in the prior art, considerable expense and effort is made to provide control arm length adjustment features so as to keep all of the control arm couplers aligned with the mating couplers of the pivotal release stanchions across the entire length of the string of stanchions. It is not uncommon for the rancher or dairyman to have to readjust the control arm lengths with each change of season, and in some areas of the country where there are significant temperature differentials between cold nights and warm days, to have to readjust the control arms on a daily basis.
Accordingly, it is an object of the present invention to eliminate the need to adjust the length of the control arm to continually realign the cooperating coupler portions of the latching mechanism so that adjustments for variations in length due to expansion and contraction of the stanchion materials is eliminated.
Another object of the present invention is to provide a latching mechanism which is simple, effective and safe for the operator.